GPU Passthrough


FredericR

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Hi there,

i tested the GPU Passthrough with an old Quadro P4000 and an cheap GT710 and can't get them to work. I want to build a new Computer for CAD with 4VMs and 4GPUs. Before i buy GPUs and these can't passthrough i thought i ask here for compatibility. I would buy Nvidia Quadro RTX4000 but i have no idea if they would work. Do somebody know, if these work or whitch quadros would definitly work? is there somewhere a List of working GPUs for passthrough?

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3 hours ago, FredericR said:

i tested the GPU Passthrough with an old Quadro P4000 and an cheap GT710 and can't get them to work. I want to build a new Computer for CAD with 4VMs and 4GPUs. Before i buy GPUs and these can't passthrough i thought i ask here for compatibility. I would buy Nvidia Quadro RTX4000 but i have no idea if they would work. Do somebody know, if these work or whitch quadros would definitly work? is there somewhere a List of working GPUs for passthrough?

"Can't get them to work" is rather vague. Need more details.

Both P4000 and GT710 are not known to be problematic so it's likely something you did wrong.

 

Note though: 

4xVMs with 4xGPUs pass-through, while theoretically possible with consumer hardware (e.g. TR4), is something probably reserved for enterprise hardware (e.g. Epyc).

It would also require a decent level of skills. You are approaching Linus level of complexity and he has a team of writers to help him do stuff (with personal help from Wendell - you can't get that being a regular Joe).

 

While you are at it: Tools -> Diagnostics -> attach zip file in your next post with details.

 

 

 

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when i try to passthrough the p4000 or gt710 i only get blackscreen on the graphicscard. Also the VM isn't reachable via ping or rdp. The VM is installed via vnc with all drivers. I tryed everything in another computer (1x old core2duo 1x fujitsu Primergy RX300 S7). I also tryed adding an explicit vbios. Today i read a thread about using another Machine i440fx-... something older i will try this today. 

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So many question marks:

  • You have 2 xml, Windows 10 and W10 Test2. The former is on VNC graphics with OVMF and the latter has GPU passed through with SeaBIOS. Each VM has its own different vdisk. Were they intentionally set up like that (e.g. you installed windows twice?)
    • No ping + no rdp = your VM didn't boot -> wrong vdisk?
  • Your test system is a i5 650 on P7H55-M motherboard with 4GB RAM. I understand you want to test things out first but that is way too far from a realistic test given what you are aiming to achieve.
    • The P4000 requires PCIe 3.0 and your motherboard has PCIe 2.0. Yes, it is supposed to be backward compatible but it just demonstrates how old your base system is - it's very hard to prove anything on that.
    • You set your VM with 2GB RAM. That is the minimum system requirement for the P4000. My Win10 VM would not even boot with 2GB RAM + GPU (albeit not Quadro).
  • You mentioned trying both SeaBIOS and OVMF. You can't casually switch between them. You have to set 1 thing up and stick with it.
    • Also, use Q35-4.1 for better PCIe support (start a new template and pick Q35 + OVMF).
  • Last but not least, you should make sure your VM works first (in terms of xml) e.g. it can boot into the Windows installer WITH GPU PASSED THROUGH and then install things from there.

 

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Thanks for your reply. The Test rig is old and this is my biggest concern. I wanted to test it with the old fujitsu Primergy but it has no PCIe Power so i only could test it with the gt710. I also have an old Computer with a i7 4770k (no vt-d)

- the 2 vm's are both for testig one installed with OVMF and one installed with SeaBIOS. Both VMs give me a blackscreen after passing through the P4000 and on both VMs there is no Ping Answer with P4000 Passthrough

- the Vdisks are the right. Without P4000 Passthrough i can access via VNC and ping both VMs

 

I will try the Q35-4.1 and the install of a new vm with GPU already passed through and give a Feedback. My biggest concern is, the hardware is to old so i spend several hours for hardware witch cant work for Passthrough. Hopefully i soon get the budget for the new computer

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2 hours ago, FredericR said:

I Build a new VM with Q35-4.1 (OVMF) and passthrough the P4000 but also get blackscreen (nothing installed, i only give it the Win10 iso)

Other things you can try:

  • Update motherboard BIOS
  • Boot Unraid in Legacy Mode (i.e. disable UEFI boot) - note: this is Unraid host settings, not VM.
  • VFIO stub the GPU (watch SpaceInvader One guide on Youtube for instruction)
  • Obtain a vbios for the P4000 (again, watch SIO guide on Youtube).

You can also try with the GT 710 instead of P4000 on the i5 650 system.

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